Reduction of the squeal noise from an automotive water pump

This paper presents a method to reduce the squeal noise generated by an automotive water pump. The noise and vibration of the water pump were analyzed through experiments, from which it was found that the squeal noise was caused by the torsional vibration of the shaft in the pump rotor system. Therefore, the water pump rotor system was modeled as an equivalent single-degree-of-freedom model for torsional vibration and the stability coefficient was established to assess the possibility of generating the squeal noise. Based on a parametric study, a design strategy was suggested to reduce the possibility of squeal noise. A sensitivity analysis showed how changes in various design parameters of the water pump affected the stability coefficient. We found that the closer the position of the mechanical seal is to the nodal point of the fundamental torsional mode of the water pump shaft, the less squeal noise is generated. It was also found that decreasing the mass moment of inertia of the pulley and increasing that of the impeller to place the seal position close to the nodal point help to suppress the squeal noise. In addition, an optimal design procedure for the water pump was presented to reduce squeal noise generation, and the water pump designed and manufactured according to this design procedure was experimentally verified to confirm that no noise was generated.